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https://mail.yahoo.com/d/search/keyword=hindawi/messages/AJsNq_oR_Ba0W0HILgF-0Lbc2nA?.intl=id&.lang=id-ID&.partner=none&.src=fp

8 Juli 2018

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Research Article

On the Locating Chromatic Number of Certain Barbell Graphs

Asmiati ,1I. Ketut Sadha Gunce Yana,1and Lyra Yulianti2

1Mathematics Department, Faculty of Mathematics and Natural Sciences, Lampung University, Jl. Brodjonegoro No.1 Bandar Lampung, Indonesia

2Mathematics Department, Faculty of Mathematics and Natural Sciences, Andalas University, Kampus UNAND Limau Manis, Padang 25163, Indonesia

Correspondence should be addressed to Asmiati; [email protected]

Received 27 March 2018; Revised 26 June 2018; Accepted 22 July 2018; Published 5 August 2018 Academic Editor: Dalibor Froncek

Copyright Β© 2018 Asmiati et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

The locating chromatic number of a graph𝐺 is defined as the cardinality of a minimum resolving partition of the vertex set 𝑉(𝐺) such that all vertices have distinct coordinates with respect to this partition and every two adjacent vertices in𝐺 are not contained in the same partition class. In this case, the coordinate of a vertexV in 𝐺 is expressed in terms of the distances of V to all partition classes. This concept is a special case of the graph partition dimension notion. In this paper we investigate the locating chromatic number for two families of barbell graphs.

1. Introduction

The partition dimension was introduced by Chartrand et al.

[1] as the development of the concept of metric dimension.

The application of metric dimension plays a role in robotic navigation [2], the optimization of threat detecting sensors [3], and chemical data classification [4]. The concept of locating chromatic number is a marriage between the parti-tion dimension and coloring of a graph, first introduced by Chartrand et al in 2002 [5]. The locating chromatic number of a graph is a newly interesting topic to study because there is no general theorem for determining the locating chromatic number of any graph.

Let 𝐺 = (𝑉, 𝐸) be a connected graph. We define the distance as the minimum length of path connecting vertices𝑒 andV in 𝐺, denoted by 𝑑(𝑒, V). A π‘˜-coloring of 𝐺 is a function 𝑐 : 𝑉(𝐺) 󳨀→ {1, 2, . . . , π‘˜}, where 𝑐(𝑒) ΜΈ= 𝑐(V) for any two adjacent vertices𝑒 and V in 𝐺. Thus, the coloring 𝑐 induces a partitionΞ  of 𝑉(𝐺) into π‘˜ color classes (independent sets) 𝐢1, 𝐢2, . . . , πΆπ‘˜, where𝐢𝑖 is the set of all vertices colored by the color𝑖 for 1 ≀ 𝑖 ≀ π‘˜. The color code 𝑐Π(V) of a vertex V in 𝐺 is defined as the π‘˜-vector (𝑑(V, 𝐢1), 𝑑(V, 𝐢2), . . . , 𝑑(V, πΆπ‘˜)), where𝑑(V, 𝐢𝑖) = min{𝑑(V, π‘₯) : π‘₯ ∈ 𝐢𝑖} for 1 ≀ 𝑖 ≀ π‘˜. The π‘˜-coloring 𝑐 of 𝐺 such that all vertices have different color codes is called a locating coloring of𝐺. The locating chromatic

number of𝐺, denoted by πœ’πΏ(𝐺), is the minimum π‘˜ such that 𝐺 has a locating coloring.

The following theorem is a basic theorem proved by Chartrand et al. [5]. The neighborhood of vertex 𝑒 in a connected graph𝐺, denoted by 𝑁(𝑒), is the set of vertices adjacent to𝑒.

Theorem 1 (see [5]). Let 𝑐 be a locating coloring in a connected graph𝐺. If 𝑒 and V are distinct vertices of 𝐺 such that 𝑑(𝑒, 𝑑) = 𝑑(V, 𝑑) for all 𝑑 ∈ 𝑉(𝐺)βˆ’{𝑒, V}, then 𝑐(𝑒) ΜΈ= 𝑐(V). In particular, if 𝑒 and V are non-adjacent vertices of 𝐺 such that 𝑁(𝑒) = 𝑁(V), then𝑐(𝑒) ΜΈ= 𝑐(V).

The following corollary gives the lower bound of the locating chromatic number for every connected graph𝐺.

Corollary 2 (see [5]). If 𝐺 is a connected graph and there is a vertex adjacent toπ‘˜ leaves, then πœ’πΏ(𝐺) β‰₯ π‘˜ + 1.

There are some interesting results related to the determi-nation of the locating chromatic number of some graphs. The results are obtained by focusing on certain families of graphs.

Chartrand et al. in [5] have determined all graphs of order 𝑛 with locating chromatic number 𝑛, namely, a complete multipartite graph of 𝑛 vertices. Moreover, Chartrand et

Hindawi

International Journal of Mathematics and Mathematical Sciences Volume 2018, Article ID 5327504, 5 pages

https://doi.org/10.1155/2018/5327504

REVISI PAPER KETIGA( REVISI MINOR )

2 International Journal of Mathematics and Mathematical Sciences

al. [6] have succeeded in constructing tree on 𝑛 vertices, 𝑛 β‰₯ 5, with locating chromatic numbers varying from 3 to 𝑛, except for (𝑛 βˆ’ 1). Then Behtoei and Omoomi [7]

have obtained the locating chromatic number of the Kneser graphs. Recently, Asmiati et al. [8] obtained the locating chromatic number of the generalized Petersen graph𝑃(𝑛, 1) for𝑛 β‰₯ 3. Baskoro and Asmiati [9] have characterized all trees with locating chromatic number 3. In [10] all trees of order 𝑛 with locating chromatic number 𝑛 βˆ’ 1 were characterized, for any integers 𝑛 and 𝑑, where 𝑛 > 𝑑 + 3 and2 ≀ 𝑑 < 𝑛/2. Asmiati et al. in [11] have succeeded in determining the locating chromatic number of homogeneous amalgamation of stars and their monotonicity properties and in [12] for firecracker graphs. Next, Wellyyanti et al. [13]

determined the locating chromatic number for complete 𝑛-ary trees.

The generalized Petersen graph𝑃(𝑛, π‘š), 𝑛 β‰₯ 3 and 1 ≀ π‘š ≀ ⌊(𝑛 βˆ’ 1)/2βŒ‹, consists of an outer 𝑛-cycle 𝑦1, 𝑦2, . . . , 𝑦𝑛, a set of 𝑛 spokes 𝑦𝑖π‘₯𝑖, 1 ≀ 𝑖 ≀ 𝑛, and 𝑛 edges π‘₯𝑖π‘₯𝑖+π‘š, 1 ≀ 𝑖 ≀ 𝑛, with indices taken modulo 𝑛. The generalized Petersen graph was introduced by Watkins in [14]. Let us note that the generalized Petersen graph𝑃(𝑛, 1) is a prism defined as Cartesian product of a cycle𝐢𝑛and a path𝑃2.

Next theorems give the locating chromatic numbers for complete graph𝐾𝑛and generalized Petersen graph𝑃(𝑛, 1).

Theorem 3 (see [6]). For 𝑛 β‰₯ 2, the locating chromatic number of complete graph𝐾𝑛is𝑛.

Theorem 4 (see [8]). The locating chromatic number of generalized Petersen graph𝑃(𝑛, 1) is 4 for odd 𝑛 β‰₯ 3 or 5 for even𝑛 β‰₯ 4.

The barbell graph is constructed by connecting two arbitrary connected graphs𝐺 and 𝐻 by a bridge. In this paper, firstly we discuss the locating chromatic number for barbell graphπ΅π‘š,𝑛forπ‘š, 𝑛 β‰₯ 3, where 𝐺 and 𝐻 are complete graphs onπ‘š and 𝑛 vertices, respectively. Secondly, we determine the locating chromatic number of barbell graph𝐡𝑃(𝑛,1)for𝑛 β‰₯ 3, where𝐺 and 𝐻 are two isomorphic copies of the generalized Petersen graph𝑃(𝑛, 1).

2. Results and Discussion

Next theorem proves the exact value of the locating chromatic number for barbell graph𝐡𝑛,𝑛.

Theorem 5. Let 𝐡𝑛,𝑛 be a barbell graph for𝑛 β‰₯ 3. Then the locating chromatic number of𝐡𝑛,𝑛isπœ’πΏ(𝐡𝑛,𝑛) = 𝑛 + 1.

Proof. Let𝐡𝑛,𝑛,𝑛 β‰₯ 3, be the barbell graph with the vertex set𝑉(𝐡𝑛,𝑛) = {𝑒𝑖, V𝑖 : 1 ≀ 𝑖 ≀ 𝑛} and the edge set 𝐸(𝐡𝑛,𝑛)

=β‹ƒπ‘›βˆ’1𝑖=1{𝑒𝑖𝑒𝑖+𝑗 : 1 ≀ 𝑗 ≀ 𝑛 βˆ’ 𝑖} βˆͺ β‹ƒπ‘›βˆ’1𝑖=1{V𝑖V𝑖+𝑗 : 1 ≀ 𝑗 ≀ 𝑛 βˆ’ 𝑖} βˆͺ {𝑒𝑛V𝑛}.

First, we determine the lower bound of the locating chromatic number for barbell graph 𝐡𝑛,𝑛 for𝑛 β‰₯ 3. Since the barbell graph𝐡𝑛,𝑛 contains two isomorphic copies of a complete graph𝐾𝑛, then with respect to Theorem 3 we have πœ’πΏ(𝐡𝑛,𝑛) β‰₯ 𝑛. Next, suppose that 𝑐 is a locating coloring

using 𝑛 colors. It is easy to see that the barbell graph 𝐡𝑛,𝑛 contains two vertices with the same color codes, which is a contradiction. Thus, we have thatπœ’πΏ(𝐡𝑛,𝑛) β‰₯ 𝑛 + 1.

To show that 𝑛 + 1 is an upper bound for the locating chromatic number of barbell graph𝐡𝑛,𝑛 it suffices to prove the existence of an optimal locating coloring𝑐 : 𝑉(𝐡𝑛,𝑛) 󳨀→

{1, 2, . . . , 𝑛 + 1}. For 𝑛 β‰₯ 3 we construct the function 𝑐 in the following way:

𝑐 (𝑒𝑖) = 𝑖, 1 ≀ 𝑖 ≀ 𝑛

𝑐 (V𝑖) = {{ {{ {{ {{ {

𝑛, for𝑖 = 1 𝑖, for2 ≀ 𝑖 ≀ 𝑛 βˆ’ 1 𝑛 + 1, otherwise.

(1)

By using the coloring𝑐, we obtain the color codes of 𝑉(𝐡𝑛,𝑛) as follows:

𝑐Π(𝑒𝑖)

= {{ {{ {{ {{ {

0, for π‘–π‘‘β„Ž component, 1 ≀ 𝑖 ≀ 𝑛

2, for (𝑛 + 1)π‘‘β„Ž component, 1 ≀ 𝑖 ≀ 𝑛 βˆ’ 1 1, otherwise,

𝑐Π(V𝑖) = {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {

0, for π‘–π‘‘β„Ž component, 2 ≀ 𝑖 ≀ 𝑛 βˆ’ 1 forπ‘›π‘‘β„Ž component, 𝑖 = 1, and for (𝑛 + 1)π‘‘β„Ž component, 𝑖 = 𝑛, 3, for 1𝑠𝑑 component, 1 ≀ 𝑖 ≀ 𝑛 βˆ’ 1 2, for 1𝑠𝑑 component, 𝑖 = 𝑛 1, otherwise.

(2)

Since all vertices in𝑉(𝐡𝑛,𝑛) have distinct color codes, then the coloring𝑐 is desired locating coloring. Thus, πœ’πΏ(𝐡𝑛,𝑛) = 𝑛 + 1.

Corollary 6. For 𝑛, π‘š β‰₯ 3, and π‘š ΜΈ= 𝑛, the locating chromatic number of barbell graphπ΅π‘š,𝑛is

πœ’πΏ(π΅π‘š,𝑛) = max {π‘š, 𝑛} . (3)

Next theorem provides the exact value of the locating chromatic number for barbell graph𝐡𝑃(𝑛,1).

Theorem 7. Let 𝐡𝑃(𝑛,1)be a barbell graph for𝑛 β‰₯ 3. Then the locating chromatic number of𝐡𝑃(𝑛,1)is

International Journal of Mathematics and Mathematical Sciences 3

πœ’πΏ(𝐡𝑃(𝑛,1)) ={ {{

4, for odd 𝑛

5, for even 𝑛. (4)

Proof. Let𝐡𝑃(𝑛,1),𝑛 β‰₯ 3, be the barbell graph with the vertex set𝑉(𝐡𝑃(𝑛,1)) = {𝑒𝑖, 𝑒𝑛+𝑖, 𝑀𝑖, 𝑀𝑛+𝑖: 1 ≀ 𝑖 ≀ 𝑛} and the edge set 𝐸(𝐡𝑃(𝑛,1)) = {𝑒𝑖𝑒𝑖+1, 𝑒𝑛+𝑖𝑒𝑛+𝑖+1, 𝑀𝑖𝑀𝑖+1,𝑀𝑛+𝑖𝑀𝑛+𝑖+1 : 1 ≀ 𝑖 ≀ 𝑛 βˆ’ 1} βˆͺ {𝑒𝑛𝑒1, 𝑒2𝑛𝑒𝑛+1, 𝑀𝑛𝑀1, 𝑀2𝑛𝑀𝑛+1} βˆͺ {𝑒𝑖𝑒𝑛+𝑖, 𝑀𝑖𝑀𝑛+𝑖: 1 ≀ 𝑖 ≀ 𝑛} βˆͺ {𝑒𝑛𝑀𝑛}.

Let us distinguish two cases.

Case 1 (𝑛 odd). According to Theorem 4 for 𝑛 odd we have πœ’πΏ(𝐡𝑃(𝑛,1)) β‰₯ 4. To show that 4 is an upper bound for the locating chromatic number of the barbell graph𝐡𝑃(𝑛,1) we describe an locating coloring𝑐 using 4 colors as follows:

𝑐 (𝑒𝑖) = {{ {{ {{ {{ {

1, for 𝑖 = 1 3, for even 𝑖, 𝑖 β‰₯ 2 4, for odd 𝑖, 𝑖 β‰₯ 3.

𝑐 (𝑒𝑛+𝑖) = {{ {{ {{ {{ {

2, for 𝑖 = 1 3, for odd 𝑖, 𝑖 β‰₯ 3 4, for even 𝑖, 𝑖 β‰₯ 2.

𝑐 (𝑀𝑖) = {{ {{ {{ {{ {

1, for odd 𝑖, 𝑖 ≀ 𝑛 βˆ’ 2 2, for even 𝑖, 𝑖 ≀ 𝑛 βˆ’ 1 3, for 𝑖 = 𝑛.

𝑐 (𝑀𝑛+𝑖) = {{ {{ {{ {{ {

1, for even 𝑖, 𝑖 ≀ 𝑛 βˆ’ 1 2, for odd 𝑖, 𝑖 ≀ 𝑛 βˆ’ 2 4, for 𝑖 = 𝑛.

(5)

For𝑛 odd the color codes of 𝑉(𝐡𝑃(𝑛,1)) are

𝑐Π(𝑒𝑖)

= {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {

𝑖, for2𝑛𝑑 component, 𝑖 ≀ 𝑛 + 1 2 𝑖 βˆ’ 1, for1𝑠𝑑component, 𝑖 ≀𝑛 + 1

2 𝑛 βˆ’ 𝑖 + 1, for 1𝑠𝑑component, 𝑖 >𝑛 + 1

2 𝑛 βˆ’ 𝑖 + 2, for 2𝑛𝑑 component, 𝑖 > 𝑛 + 1 0, for3π‘‘β„Ž component, 𝑖 even, 𝑖 β‰₯ 22

for4π‘‘β„Ž component, 𝑖 odd, 𝑖 β‰₯ 3 1, otherwise.

𝑐Π(𝑒𝑛+𝑖)

= {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {

𝑖, for1𝑠𝑑 component, 𝑖 ≀𝑛 + 1 2 𝑖 βˆ’ 1, for2𝑛𝑑 component, 𝑖 ≀ 𝑛 + 1

2 𝑛 βˆ’ 𝑖 + 1, for 2𝑛𝑑 component, 𝑖 > 𝑛 + 1

2 𝑛 βˆ’ 𝑖 + 2, for 1𝑠𝑑 component, 𝑖 >𝑛 + 1 0, for4π‘‘β„Ž component, 𝑖 even, 𝑖 β‰₯ 22

for3π‘‘β„Ž component, 𝑖 odd, 𝑖 β‰₯ 3 1, otherwise.

𝑐Π(𝑀𝑖)

= {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {

𝑖, for3π‘‘β„Ž component, 𝑖 ≀ 𝑛 βˆ’ 1 2 𝑖 + 1, for4π‘‘β„Ž component, 𝑖 ≀ 𝑛 βˆ’ 1

2 𝑛 βˆ’ 𝑖, for3π‘‘β„Ž component, 𝑖 β‰₯ 𝑛 + 1

2 𝑛 βˆ’ 𝑖 + 1, for 4π‘‘β„Ž component, 𝑖 β‰₯ 𝑛 + 1 0, for2𝑛𝑑 component, 𝑖 even, 𝑖 ≀ 𝑛 βˆ’ 12

for1𝑠𝑑 component, 𝑖 odd, 𝑖 ≀ 𝑛 βˆ’ 2 1, otherwise.

𝑐Π(𝑀𝑛+𝑖)

= {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {

𝑖, for4π‘‘β„Ž component, 𝑖 ≀ 𝑛 βˆ’ 1 2 𝑖 + 1, for3π‘‘β„Ž component, 𝑖 ≀ 𝑛 βˆ’ 1

2 𝑛 βˆ’ 𝑖, for4π‘‘β„Ž component, 𝑖 β‰₯ 𝑛 + 1

2 𝑛 βˆ’ 𝑖 + 1, for 3π‘‘β„Ž component, 𝑖 β‰₯ 𝑛 + 1 0, for1𝑠𝑑 component, 𝑖 even, 𝑖 ≀ 𝑛 βˆ’ 12

for2𝑛𝑑 component, 𝑖 odd, 𝑖 ≀ 𝑛 βˆ’ 2 1, otherwise.

(6) Since all vertices in𝐡𝑃(𝑛,1)have distinct color codes, then the coloring𝑐 with 4 colors is an optimal locating coloring and it proves thatπœ’πΏ(𝐡𝑃(𝑛,1)) ≀ 4.

Case 2 (𝑛 even). In view of the lower bound from Theorem 7 it suffices to prove the existence of a locating coloring𝑐 : 𝑉(𝐡𝑃(𝑛,1)) 󳨀→ {1, 2, . . . , 5} such that all vertices in 𝐡𝑃(𝑛,1) have distinct color codes. For𝑛 even, 𝑛 β‰₯ 4, we describe the locating coloring in the following way:

𝑐 (𝑒𝑖) = {{ {{ {{ {{ {{ {{ {{ {

1, for 𝑖 = 1

3, for even 𝑖, 2 ≀ 𝑖 ≀ 𝑛 βˆ’ 2 4, for odd 𝑖, 3 ≀ 𝑖 ≀ 𝑛 βˆ’ 1 5, for 𝑖 = 𝑛.

4 International Journal of Mathematics and Mathematical Sciences

𝑐 (𝑒𝑛+𝑖) = {{ {{ {{ {{ {

2, for 𝑖 = 1 3, for odd 𝑖, 𝑖 β‰₯ 3 4, for even 𝑖, 𝑖 β‰₯ 2.

𝑐 (𝑀𝑖) = {{ {{ {{ {{ {{ {{ {{ {

1, for odd 𝑖, 𝑖 ≀ 𝑛 βˆ’ 3 2, for even 𝑖, 𝑖 ≀ 𝑛 βˆ’ 2 3, for 𝑖 = 𝑛 βˆ’ 1 4, for 𝑖 = 𝑛.

𝑐 (𝑀𝑛+𝑖) = {{ {{ {{ {{ {

1, for even 𝑖, 𝑖 ≀ 𝑛 βˆ’ 2 2, for odd 𝑖, 𝑖 ≀ 𝑛 βˆ’ 1 5, for 𝑖 = 𝑛.

(7) In fact, our locating coloring of 𝐡𝑃(𝑛,1), 𝑛 even, has been chosen in such a way that the color codes are

𝑐Π(𝑒𝑖)

= {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {

𝑖, for2𝑛𝑑 and5π‘‘β„Žcomponents, 𝑖 ≀ 𝑛 2 𝑖 βˆ’ 1, for1𝑠𝑑component, 𝑖 ≀𝑛

2 𝑛 βˆ’ 𝑖, for5π‘‘β„Žcomponent, 𝑖 > 𝑛 2 𝑛 βˆ’ 𝑖 + 1, for 1𝑠𝑑component, 𝑖 >𝑛 2 𝑛 βˆ’ 𝑖 + 2, for 2𝑛𝑑 component, 𝑖 >𝑛

2

0, for3π‘‘β„Žcomponent, 𝑖 even, 2 ≀ 𝑖 ≀ 𝑛 βˆ’ 2 for4π‘‘β„Žcomponent, 𝑖 odd, 3 ≀ 𝑖 ≀ 𝑛 βˆ’ 1 2, for4π‘‘β„Žcomponent, 𝑖 = 1

for3π‘‘β„Žcomponent, 𝑖 = 𝑛 1, otherwise.

𝑐Π(𝑒𝑛+𝑖)

= {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {

𝑖, for1𝑠𝑑component, 𝑖 ≀𝑛 2 𝑖 βˆ’ 1, for2𝑛𝑑 component, 𝑖 ≀𝑛

2 𝑛 + 𝑖, for5π‘‘β„Žcomponent, 𝑖 ≀ 𝑛 2

𝑛 βˆ’ 𝑖 + 1, for 2𝑛𝑑 and5π‘‘β„Žcomponents, 𝑖 > 𝑛 2 𝑛 βˆ’ 𝑖 + 2, for 1π‘‘β„Žcomponent,𝑖 >𝑛

2

0, for3π‘‘β„Žcomponent, 𝑖 odd, 3 ≀ 𝑖 ≀ 𝑛 βˆ’ 1 for4π‘‘β„Žcomponent, 𝑖 even, 2 ≀ 𝑖 ≀ 𝑛 2, for3π‘‘β„Žcomponent, 𝑖 = 1

1, otherwise.

𝑐Π(𝑀𝑖)

= {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {

𝑖, for4π‘‘β„Žcomponent, 𝑖 ≀ 𝑛 2 𝑖 + 1, for5π‘‘β„Žcomponent, 𝑖 ≀ 𝑛 2 for3π‘‘β„Žcomponent, 𝑖 ≀ 𝑛

2βˆ’ 1 𝑛 βˆ’ 𝑖, for4π‘‘β„Žcomponent, 𝑖 > 𝑛

2 𝑛 βˆ’ 𝑖 + 1, for 5π‘‘β„Žcomponent, 𝑖 > 𝑛 2 𝑛 βˆ’ 𝑖 βˆ’ 1, for 3π‘‘β„Žcomponent, 𝑛

2≀ 𝑖 ≀ 𝑛 βˆ’ 1 0, for1𝑠𝑑component, 𝑖 odd, 𝑖 ≀ 𝑛 βˆ’ 3

for2𝑛𝑑 component, 𝑖 even, 𝑖 ≀ 𝑛 βˆ’ 2 2, for1𝑠𝑑component, 𝑖 = 𝑛 βˆ’ 1

for2𝑛𝑑 component, 𝑖 = 𝑛 1, otherwise.

𝑐Π(𝑀𝑛+𝑖)

= {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {{ {

𝑖, for5π‘‘β„Žcomponent, 𝑖 ≀ 𝑛 2 𝑖 + 1, for4π‘‘β„Žcomponent, 𝑖 ≀ 𝑛 2 𝑖 + 2 for3π‘‘β„Žcomponent, 𝑖 ≀ 𝑛

2βˆ’ 1 𝑛 βˆ’ 𝑖, for3π‘‘β„Žcomponent, 𝑛

2≀ 𝑖 ≀ 𝑛 βˆ’ 1 for5π‘‘β„Žcomponent, 𝑖 > 𝑛

2 𝑛 βˆ’ 𝑖 + 1, for 4π‘‘β„Žcomponent, 𝑖 > 𝑛

0, for1𝑠𝑑component, 𝑖 even, 𝑖 ≀ 𝑛 βˆ’ 22

for2𝑛𝑑 component, 𝑖 odd, 𝑖 ≀ 𝑛 βˆ’ 1 2, for1𝑠𝑑and3π‘‘β„Žcomponents, 𝑖 = 𝑛 1, otherwise.

(8)

Since for𝑛 even all vertices of 𝐡𝑃(𝑛,1)have distinct color codes then our locating coloring has the required properties and πœ’πΏ(𝐡𝑃(𝑛,1)) ≀ 5. This concludes the proof.

Data Availability

The data used to support the findings of this study are available from the corresponding author upon request.

Conflicts of Interest

The authors declare that they have no conflicts of interest.

Acknowledgments

The authors are thankful to DRPM Dikti for the Fundamental Grant 2018.

International Journal of Mathematics and Mathematical Sciences 5

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